Joint USAF/NOAA Solar Geophysical Activity Report and Forecast 27 December 2021

Joint USAF/NOAA Solar Geophysical Activity Report and Forecast
SDF Number 361 Issued at 2200Z on 27 Dec 2021

IA. Analysis of Solar Active Regions and Activity from 26/2100Z to 27/2100Z: Solar activity has been at low levels for the past 24 hours. The largest solar event of the period was a C1 event observed at 27/0227Z. There are currently 4 numbered sunspot regions on the disk.

IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare on days one, two, and three (28 Dec, 29 Dec, 30 Dec).

IIA. Geophysical Activity Summary 26/2100Z to 27/2100Z: The geomagnetic field has been at quiet to active levels for the past 24 hours. Solar wind speed reached a peak of 507 km/s at 26/2213Z. Total IMF reached 15 nT at 27/1359Z. The maximum southward component of Bz reached -10 nT at 27/1050Z. Electrons greater than 2 MeV at geosynchronous orbit reached a peak level of 3210 pfu.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be at quiet to unsettled levels on days one and three (28 Dec, 30 Dec) and quiet to active levels on day two (29 Dec).

III. Event probabilities 28 Dec-30 Dec
Class M 20/20/20
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 27 Dec 124
Predicted 28 Dec-30 Dec 125/122/120
90 Day Mean 27 Dec 092

V. Geomagnetic A Indices
Observed Afr/Ap 26 Dec 002/003
Estimated Afr/Ap 27 Dec 007/008
Predicted Afr/Ap 28 Dec-30 Dec 010/010-011/012-007/010

VI. Geomagnetic Activity Probabilities 28 Dec-30 Dec
A. Middle Latitudes
Active 25/35/25
Minor Storm 05/15/05
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor Storm 30/30/30
Major-severe storm 30/45/30